[CLN] hr_skills: cleanup cerification reporting

>
> Due to LMS (Learning Management System) and Skills refactor we ended up having two reports about certifications. This PR cleans it.
> Reference: https://tinyurl.com/2cf2ogoq
>
> Task: 5246246

Author: HashemKhaled

addons/hr_skills/report/hr_employee_certification_report_views.xml

@@ -45,27 +45,4 @@
         </field>
     </record>
 
-    <record id="hr_employee_certification_report_action" model="ir.actions.act_window">
-        <field name="name">Certification</field>
-        <field name="res_model">hr.employee.certification.report</field>
-        <field name="search_view_id" ref="hr_employee_certification_report_view_search"/>
-        <field name="view_mode">list,pivot</field>
-        <field name="context">{
-            'search_default_employee': 1,
-        }</field>
-        <field name="help" type="html">
-            <p class="o_view_nocontent_empty_folder">
-            </p><p>
-                This report will give you an overview of the certification per Employee.
-                Create them in configuration and add them on the Employee.
-            </p>
-        </field>
-    </record>
-
-    <menuitem
-        id="hr_employee_certification_report_menu"
-        name="Certifications"
-        action="hr_employee_certification_report_action"
-        parent="hr_skills.hr_employee_skill_report_menu"
-        sequence="25"/>
 </odoo>

addons/hr_skills/report/hr_employee_skill_report_views.xml

@@ -89,6 +89,6 @@
         id="hr_employee_skill_inventory_report_menu"
         name="Skills Inventory"
         action="hr_employee_skill_report_action"
-        parent="hr_skills.hr_employee_skill_report_menu"
+        parent="hr.hr_menu_hr_reports"
         sequence="15"/>
 </odoo>

addons/hr_skills/views/hr_views.xml

@@ -593,7 +593,7 @@
         <field name="res_model">hr.employee.skill</field>
         <field name="path">certifications</field>
         <field name="domain">[('is_certification', '=', True)]</field>
-        <field name="context">{'show_employee': True, 'search_default_group_by_type': 1}</field>
+        <field name="context">{'show_employee': True}</field>
         <field name="view_mode">list,form</field>
         <field name="view_ids" eval="[(5, 0, 0),
             (0, 0, {'view_mode': 'list', 'view_id': False}),
@@ -608,12 +608,6 @@
         sequence="7"
         groups="hr.group_hr_user"/>
 
-    <menuitem
-    id="hr_employee_skill_report_menu"
-    name="Skills"
-    parent="hr.hr_menu_hr_reports"
-    sequence="15"/>
-
     <menuitem
         id="hr_skill_learning_menu"
         name="Learning"